30 March 2020
An unusual fatal flow failure in a large sand heap in China
Posted by Dave Petley
An unusual fatal flow failure in a large sand pile in China
In the evening of 27 March 2020 a large failure occurred in what is reported to have been a sand heap (I suspect in reality that this is not simple sand) at the Guizhou Commercial Concrete Co., Ltd. in Guiyang, the capital of Guizhou province in China. At the time of writing this landslide is reported to have killed seven people, of whom four have been recovered. The recovery operation continues for the other three victims. A further nine people were injured in the failure.
It is quite difficult to get a true sense of what has happened at this site; this is a somewhat unusual landslide and the reporting that I have tracked down, in both Mandarin and English, is not detailed. The best image I have found that gives a sense of this event is on the News 163 website, in Mandarin:-
An overview of the sand heap landslide on 27 March 2020 at the Guizhou Commercial Concrete Co., Ltd. in Guiyang. Image from News 163.
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The landslide appears to have occurred in the sand heap closest to the camera, with the scarp located close to the two vehicles. Three vehicles seem to be located at the foot of the landslide scarp. The sand (and some much coarser material) has flowed towards the left side of the image through and around the buildings.
Other images from News 163 suggest that this was a highly mobile failure. The image below for example shows a courtyard between the buildings, presumably to the left of the area in the first image:-
Some of the damage caused by the sand heap landslide on 27 March 2020 at the Guizhou Commercial Concrete Co., Ltd. in Guiyang. Image from News 163.
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The image suggests that this flow had a high water content and high mobility – indeed this looks like a liquefaction failure or flowslide. The landslide has travelled a considerable distance, felling large storage tanks and moving concrete mixer trucks. Note that the damaged trucks and displaced sand extend to the building at the far end of the second image.
A simple interpretation is that this is a large rotational landslide that has transitioned into a highly mobile flow. However, the reasons why this has occurred are less clear to me.
The nearest similar landslide I can think of immediately is the huge construction waste slide in Shenzhen in 2015, but that was an event on a different scale.
Can anyone else think of a landslide that is an analogue to this one?
Dave Petley is the Vice-Chancellor of the University of Hull in the United Kingdom. His blog provides commentary and analysis of landslide events occurring worldwide, including the landslides themselves, latest research, and conferences and meetings.
No analogous landslides come to mind, but I’m willing to hypothesize a mechanism.
You can see very wet material dumped down the faces of slopes in the background. Given that the slopes are all angle of repose, and have “streaky” coloration, it would seem that the hillside may be a waste dump (or spoil tip, depending on your vernacular).
Cement aggregate plants often have wash processes that remove the fine sand and silt from the processed coarse product, leaving a very wet waste. Based on the wet material on intact slopes (that even have some evidence of flow), it could be (and this is entirely speculative) that this was static liquefaction of wet waste materials, which is a depressingly common mechanism of failure in mining.
[Thanks Murray, I think that is a very interesting observation, and it seems entirely compatible with the observations. I agree that this was a static liquefaction event. D.]
I think the location on Google Earth is 26°37’45.67″N 106°34’08.04″E.
The tanks that are laying down in the lower photo are visible in the lower left of the top photo, as is the truck that is pushed into the building. In your lower photo, in the center of the left side, it appears that the mud splashed up over the top of one of the trucks.
On Google Earth you can see that there were settlement tanks between the “scarp” and the buildings. Is it possible the slide went into the tanks and the mud in the bottom of the tanks is what flowed through the rest of the plant?
After looking at a broader view on Google Earth, I see that the location of the plant is at a place called “Loess Kiln”. Is that a hint about the material? Although I’ve never heard of using loess in concrete.